Mainsail leading edge slat.

Discussion in 'Sailboats' started by Omeron, Jul 20, 2007.

  1. Omeron
    Joined: Feb 2007
    Posts: 163
    Likes: 2, Points: 0, Legacy Rep: 31
    Location: Istanbul

    Omeron Senior Member

    We know that masts are always a problem as it is not an ideal
    leading edge form for the mainsail.
    STOL aircrafts (short take off and landing) and indeed all commercial aircraft
    deploy a leading edge slat where high lift and high stall angles (30 degrees)
    are required during take off.
    How about doing the same with our masts. If a section all along the mast,
    forward of the mast, and hinged to the mast, so that it pivots and tacks
    itself arond the mast is deployed, would that create a better infow
    into the mainsail, by sucking some of the air windward of the mast, and
    regulate the otherwise turbulant air entering the mainsail.
    Has this been tried before?
    How would this contraption be viewed, in terms of sail measurement?
    Would it be wieved as part of the sail, or as part of the mast?
    I am unable to draw a picture here, but if you google STOL aircraft,
    you get all the facts and benefits of a leading edge slat.
    This is ofcourse all about windward work, but i do not think it would hurt
    downwind, as it would be just another surface creating additional drag.
    What kind of shock and horror this would create for IRC measurers i have no idea. :)
     
  2. tspeer
    Joined: Feb 2002
    Posts: 2,223
    Likes: 185, Points: 63, Legacy Rep: 1673
    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    Leading edge slats already exist for conventional rigs to do what you describe. Sailors call them "jibs".
     
  3. yipster
    Joined: Oct 2002
    Posts: 3,486
    Likes: 95, Points: 58, Legacy Rep: 1148
    Location: netherlands

    yipster designer

    on cats i've seen the jib placed more windward
    model boats on sailing channel with aerorigs use
    a short extra pivoting boom on top of the fwd coming boom
    to ofset the jib as well but havent seen that live sized yet.
     
  4. Doug Lord

    Doug Lord Guest

    Slat/jib

    I used a rectangular 2.5" X 75" "jib" on a model cat. It had a ball bearing pivoting, articulating boom set up top and bottom to place the slat in the position Marchaj said would be ideal in his first book(I think-could have been the second book).The thing tacked well and seemed to have an effect greater than it's area would suggest. I was mainly interested in working out the physics of mounting a "soft" slat. Light air performance of the boat was improved considerably. Hope to experiment with full size versions soon.
     
  5. Omeron
    Joined: Feb 2007
    Posts: 163
    Likes: 2, Points: 0, Legacy Rep: 31
    Location: Istanbul

    Omeron Senior Member

    tspeer, very clever. i like it.
    It is one hell of a slat though...

    In this case i am proposing a mini slat in between.

    With a chord length no more than twice the longitudinal axis of the mast.

    How about that?
     
  6. yipster
    Joined: Oct 2002
    Posts: 3,486
    Likes: 95, Points: 58, Legacy Rep: 1148
    Location: netherlands

    yipster designer

    Doug, that’s good to hear and makes me look forward even more to Marchaj’s books
     

  7. brian eiland
    Joined: Jun 2002
    Posts: 4,788
    Likes: 157, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.